Demon needs a name

There's this bad guy that happens to be a several hundred year old demon in the novel I'm writing, and I originally had the name Keir, but I feel it doesn't really fit with him. I'm looking for something on the darker side, I just can't seem to come up with anything good.

Are looking at an actual name that just sounds dark, like Valdemar, or a more unusual verging on made up name, like Clith?

“I read books when I was a kid, lots of books. Books always seemed like magic to me. They took you to the most amazing places. When I got older, I realized I couldn't find books that took me to all the places I wanted to go. To go to those places, I had to write some books myself.”
― Pat Murphy, The Wild Girls

"Like everyone else, I am going to die. But the words – the words live on..."
― J. Michael Straczynski

“I read books when I was a kid, lots of books. Books always seemed like magic to me. They took you to the most amazing places. When I got older, I realized I couldn't find books that took me to all the places I wanted to go. To go to those places, I had to write some books myself.”
― Pat Murphy, The Wild Girls

"Like everyone else, I am going to die. But the words – the words live on..."
― J. Michael Straczynski